FR2876372A1 - GENERATING COMPOSITION OF GAS. - Google Patents

Abstract

The invention relates to a composition comprising a fuel, an oxidant and a compound selected from the group consisting of a phosphoric acid compound or a salt thereof.Application including systems for triggering the inflation of automobile airbags.

Description

The present invention relates to a gas generating composition, adapted

  for an air bag (airbag) restraint system for automobiles, and, as well as a molded article based on this composition.

  Compositions containing sodium azide (sodium nitrogen) have been widely used as gas-generating compositions for airbag (air bag) systems used in the past as occupant protection devices in a vehicle. vehicle. However, the toxicity of sodium azide in humans [LD50 (oral flow) = 27 mg / kg)] and a hazard when handled were considered problematic, and safe compositions generating a gas, which contain different nitrogenous organic compounds, in other words "azide-free gas generating compositions" have been developed as an alternative.

  US-A-4,909,549 discloses a composition comprising a tetrazole or triazole compound containing hydrogen and an oxidizing compound containing oxygen.

  US-B No. 4,370,181 discloses a gas-generating composition comprising a metal salt of a tetrazole compound containing no hydrogen and an oxidizer containing no oxygen. US-A-4,369,079 discloses a gas-generating composition comprising a metal salt of a non-hydrogen containing biterazole compound and an alkali metal nitrate, an alkali metal nitrite, a nitrate of alkaline earth metal, an alkaline earth metal nitrite or a mixture of such substances. US Pat. No. 5,542,999 discloses a gas generating composition comprising a fuel such as GTZ, TAGN (triaminoguanidine nitrate), NG (nitroguanidine), NTO, etc., a basic copper nitrate, a catalyst for reducing toxic gases, and a refrigerant. US-A-5,608,183 discloses a gas-generating composition comprising a fuel such as guanidine nitrate, basic copper nitrate and guar gum.

  However, a residue (mist or "mist") is generated after combustion with the azide-free gas-generating compositions of the aforementioned type, and a filter is necessary to prevent a residue from entering the airbag. In such a case, a method can be used to prepare a composition which easily forms slag or easily trapped by the filter after the combustion of the gas generating composition.

  US-A-6,143,102 discloses the addition of silica as a slag-forming agent in a composition comprising a fuel such as guanidine nitrate, basic copper nitrate and a metal oxide such as alumina, so that excellent slags (clinker) are formed. JP-A No. 10-502610 teaches that the combustion temperature is reduced by the addition of a glass powder to a fuel such as a tetrazole compound and strontium nitrate, and as a result the NOx and CO content is reduced and therefore solid slag is formed. U.S. Patent No. 5,104,466 (JP-A No. 5-70109) discloses a reduction in the amount of mist using a mixture of an alkali metal azide, oxidant-containing pellets, and particles comprising a substance containing silica.

  Although it is possible to reduce the composition temperature and reduce the NOx content, etc. by means of the addition of a glass powder as described in JP-A N 10-502610, this process can be further improved, especially since the glass powder is expensive, and the weight of the Gas generating composition is increased with such a method.

  The present invention solves the problems resulting from the process involving the addition of glass powder by providing a novel gas generating composition adapted to easily form slag and reduce the NOx, CO, etc. content. As a means for solving the aforementioned problems of the state of the art, the inventor of the present invention has already filed a request for an invention concerning a combination of a glass powder, aluminum oxide, etc. (JP-A N Patent 2005-145718 equivalent to Japanese Patent Application N 2003-364024).

  In the course of research relating to the above invention, the inventors have paid great attention to the state of the combustion residue after the gas-generating composition is burned, as well as to the post-combustion levels of the fuel. N0x and CO, etc. As a result of further research, they discovered that a post-combustion residue state and a reduction in NOx and CO amounts, equivalent to cases where glass powder is used, can be achieved by using of a phosphate, by which they have arrived at the present invention.

  Thus, as a means for solving the above problem, the present invention provides a gas generating composition, which comprises: (a) a fuel, (b) an oxidant, and (c) a compound selected from the group consisting of an acidic compound phosphoric acid or a salt thereof.

  The gas-generating composition and the molded article formed with this composition according to the present invention comprise a compound selected from the group consisting of a phosphoric acid compound or a salt thereof; as a result, the combustion residue does not become a mist discharged outside the inflation system, since the combustion residue solidifies and forms slag. In addition, when the gas-generating composition comprises a phosphate or a salt thereof, etc., post-combustion NO x and CO levels can be reduced.

  Preferred embodiments of the invention will now be described.

  According to a particularly advantageous embodiment, the gas-generating composition has one or more of the following characteristics: the content of compound (c) in the composition ranges from 0.1 to 5% by weight; the composition further comprises: (d) aluminum hydroxide and / or magnesium hydroxide; the composition further comprises: (e) a binder, and / or (f) an additive.

  The invention also relates to a molded article based on the aforementioned gas-generating composition, which is in the form of a single-perforated cylinder or in the form of a porous cylinder, such as obtained by extrusion and molding of said gas generating composition.

  The compositions and molded articles of the invention also advantageously have the following characteristics.

  Component (a) The fuel forming component (a) used in the present invention comprises at least one constituent selected from tetrazole, guanidine, triazine and nitroamine compounds. By using any of the elements listed for component (a), an object of the present invention is achieved and the effect provided by the invention can be achieved.

  A preferred example of tetrazole compounds includes aminotetrazole, ammonium salts of biterazole, and the like. A preferred example of guanidine compounds includes a salt of guanidine nitrate (guanidine nitrate), aminoguanidine nitrate, nitroguanidine, triaminoguanidine nitrate, and the like. A preferred example of triazine compounds includes melamine, cyanuric acid, ammeline, ammelide, ammeland, etc. A preferred example of nitroamine-type compounds include cyclo-1,3,5-trimethylene-2,4,6trinitramine.

  Component (b) The oxidant forming component (b) used in the present invention comprises at least one constituent selected from component (b-1), namely a basic metal nitrate, a nitrate or an ammonium nitrate, and the component (b-2) formed by perchlorate or chlorate. By using any of the elements listed for component (b), an object of the present invention is achieved and the effect provided by the invention can be achieved.

  An example of a basic metal nitrate salt forming component (b1) includes at least one constituent selected from basic copper nitrate, basic cobalt nitrate, basic zinc nitrate, basic manganese nitrate, basic iron nitrate , a basic molybdenum nitrate, a basic bismuth nitrate and basic selenium nitrate.

  To increase the burning rate, the average particle size of the base metal nitrate is preferably not more than 30 μm and more preferably not more than 10 μm. In this case, the average particle size is measured by means of a particle size distribution method using laser diffraction. That of a basic metal nitrate which has been dispersed in water and is then exposed to ultrasonic waves for 3 minutes is used as a measurement sample; the cumulative value of the 50% particle count (D50) is determined and the average particle size is considered to be the average of two measurements.

  The nitrate forming component (b1) includes alkali metal nitrate, such as, for example, potassium nitrate, sodium nitrate, etc., and alkaline earth metal nitrates, such as, for example, strontium nitrate, etc. The perchlorate or chlorate forming component (b-2) is a component which not only has an oxidizing effect, but also a combustion promoting action. The term "oxidation effect" refers to an effect that allows efficient combustion of oxygen reproduction during combustion and also reduces the amount of toxic gas such as ammonia and CO, which are produced. On the other hand, the term "combustion promoting action" refers to an action by which ignition of the gas generating composition is increased and the rate of combustion is increased.

  The perchlorates or chlorates selected include in particular at least one element selected from ammonium perchlorate, potassium perchlorate, sodium perchlorate, potassium chlorate and sodium chlorate.

  Component (c) Component (c) used in the present invention is a component that retains the mist generated by combustion and forms slag. The presence of component (c) in the gas-generating composition inhibits the formation of a mist-shaped combustion residue, being discharged outside the inflator, and entering the airbag.

  Examples of component (c) include one of the following substances (or a combination of at least two of these substances) namely: a phosphoric acid compound or a salt thereof, such as phosphoric acid, phosphorous acid, hydrophosphoric acid, pyrophosphoric acid, metaphosphoric acid, polyphosphoric acid, ultraphosphoric acid, and the like. In addition, the salts indicated below may be used in the form of crystals or anhydrous substances. By using any of the elements listed for component (c), an object of the present invention is achieved and the effect of the present invention can be achieved.

  Phosphate dihydrogenated potassium phosphate salts, hydrogenated potassium phosphate and tribasic potassium phosphate; sodium dihydrogen phosphate, sodium hydrogen phosphate, and tribasic sodium phosphate; calcium dihydrogen phosphate, hydrogenated calcium phosphate, and tribasic calcium phosphate; dihydrogenated magnesium phosphate, hydrogenated magnesium phosphate, and tribasic magnesium phosphate; ammonium dihydrogen phosphate, hydrogenated ammonium phosphate, and tribasic ammonium phosphate, etc. Phosphite salts Phosphite sodium, sodium hypophosphite, etc. Pyrophosphate salts Sodium pyrophosphate and dihydrogen pyrophosphate sodium; calcium pyrophosphate and calcium dihydrogen pyrophosphate; potassium pyrophosphate, calcium pyrophosphate and magnesium pyrophosphate, etc. Metaphosphate salts Sodium metaphosphate, Potas-30 sium metaphosphate, magnesium metaphosphate and aluminum metaphosphate, etc. Polyphosphate salts Sodium tripolyphosphate, sodium tetrapolyphosphate, sodium pentapolyphosphate, potassium tripolyphosphate, calcium dihydrogen pyrophosphate, dicalcium pyrophosphate, etc. Salts of ultraphosphate Ultraphosphate of sodium, etc. Of the above-mentioned products, preferred examples of component (c) include potassium dihydrogen phosphate, potassium tripolyphosphate, potassium metaphosphate, calcium dihydrogen pyrophosphate, calcium pyrophosphate, sodium tripolyphosphate, magnesium metaphosphate , aluminum metaphosphate and tribasic aluminum phosphate.

  Component (d) The present invention may also contain component (d), aluminum hydroxide and / or magnesium hydroxide. Aluminum hydroxide and magnesium hydroxide may be used alone or in combination. By using any of the elements listed for component (d), an object of the present invention is achieved and the effect provided by the invention can be achieved.

  The aluminum hydroxide and the magnesium hydroxide of component (d) have low toxicity, have a high initial decomposition temperature and, when subjected to thermal decomposition, they absorb a large amount of heat and generate aluminum oxide or magnesium oxide and water. By including aluminum hydroxide and / or magnesium hydroxide in the gas-generating composition, the combustion temperatures are reduced and lower amounts of toxic post-combustion NOx and CO are formed.

  Component (e) The present invention may also contain component (e), namely a binder. By using any of the substances listed for component (d), an object of the present invention is achieved and the effect provided by the invention can be achieved.

  The binder of component (e) may be one, two or more, substance (s) chosen from carboxymethylcellulose (CMC), carboxymethylcellulose-sodium (CMCNa), carboxymethylcellulose-potassium, carboxymethylcellulose ammonium acetate, cellulose acetate, cellulose acetateburyrate (CAB), methylcellulose (MC), ethylcellulose (EC), hydroxyethylcellulose (HEC), ethylhydroxyethylcellulose (EHEC), hydroxypropylcellulose (HPC) ), carboxymethylethylcellulose (CMEC), microcrystalline cellulose, polyacrylamide, polyacrylamide aminosic compounds, polyacrylic hydrazide, acrylamide acid-metal salt copolymer of acrylic acid, polyacrylamide compound-polyacrylic acid ester copolymer , polyvinyl alcohol, acrylic rubber, guar gum, starch and silicone.

  Among the substances indicated previously as binder are preferred sodium carboxymethylcellulose (CMCNa) and guar gum, especially given their cohesion, cost, and ignition characteristics.

  Component (f) The present invention may also contain a component (f) as an additive. By using any of the products listed for component (f), an object of the present invention is achieved and the effect provided by the invention can be achieved.

  The additive forming component (f) may be one, two or more of two substances selected from metal oxides, such as copper oxide, iron oxide, zinc oxide, cobalt oxide manganese oxide, molybdenum oxide, nickel oxide, bismuth oxide, gallium oxide, silica, alumina, etc .; metal carbonates or basic metal carbonates such as cobalt carbonate, calcium carbonate, magnesium carbonate, basic zinc carbonate, basic copper carbonate, etc .; complexes of metal oxides or hydroxides such as, for example, acidic clay, kaolin, talc, bentonite, diatomaceous earth, hydrotalcite, etc .; salts of oxometallic acids such as sodium silicate, mica molybdate, cobalt molybdate, ammonium molybdate, etc .; molybdenum disulfide, calcium stereol, silicon nitride and silicon carbide. These additives can reduce the combustion temperature of the gas generating composition, regulate the rate of combustion and reduce the amounts of toxic post-combustion NOx and CO products that are produced.

  Among these additives, copper oxide, iron oxide and manganese oxide are preferred.

  Content of constituents in the composition (1) First combination When the composition of the present invention contains three components (a), (b) and (c), the contents indicated below of the respective constituents is preferred in order to achieve an object of the present invention.

  The content of the fuel forming component (a) is preferably from 35 to 60% by weight, more preferably from 40 to 60% by weight and still more preferably from 40 to 55% by weight.

  The content of the oxidant forming component (b) is preferably from 30 to 70% by weight, more preferably from 35 to 65% by weight, and still more preferably from 45 to 55% by weight. .

  The content of the phosphoric acid compound, or salt thereof, constituting component (c) is preferably from 0.1 to 5% by weight, more preferably from 0.2 to 3% by weight and from more preferably from 0.5 to 1.5% by weight.

  (2) Second combination When the composition of the present invention contains four components (a), (b), (c) and (d), the contents indicated below, of the respective constituents is preferred to achieve the purpose of this invention. invention.

  The content of the fuel forming component (a) is preferably from 30 to 60% by weight, more preferably from 35 to 55% by weight and still more preferably from 35 to 50% by weight.

  The content of the oxidant forming component (b) is preferably from 35 to 70% by weight, more preferably from 40 to 60% by weight and still more preferably from 45 to 55% by weight.

  The content of the phosphoric acid compound, or salt thereof, constituting component (c) is preferably from 0.1 to 5% by weight, more preferably from 0.2 to 3% by weight and from even more preferentially from 0.5 to 1.5% by weight.

  The content of aluminum hydroxide and / or magnesium hydroxide forming component (d) is preferably from 0.5 to 15% by weight, more preferably from 2 to 12% by weight and from even more preferentially from 3 to 10% by weight.

  When the percentage of component (d) is within the ranges indicated above, not only can the amount of toxic NOx and CC be reduced in combination with the reduction of the combustion temperature, but also when the composition of the present invention is reduced. is used in an air bag inflator, a burning rate necessary for the expansion and deployment of the airbag in the desired time interval can be guaranteed.

  From the standpoint of improving the vapor entrapment efficiency, the combined percentage of content of component (c) and component (d) in the present invention preferably ranges from 0.5 to 20% by weight. mass, more preferably from 2 to 15% by weight and even more preferably from 3 to 10% by weight.

  Similarly, from the point of view of increasing the vapor entrapment efficiency, the mass content of component (c) and component (d) in the present invention [(d) / (c) preferably ranges from 1 to 20, more preferably from 2 to 15 and still more preferably from 3 to 10.

  (3) Third combination When the composition of the present invention contains four components (a), (b), (c) and (e), the contents indicated below, respective constituents is preferred to achieve a goal. of the present invention.

  The content of the fuel forming component (a) is preferably from 25 to 55% by weight, more preferably from 30 to 55% by weight, and still more preferably from 35 to 45% by weight.

  The content of the oxidant forming component (b) is preferably from 35 to 70% by weight, more preferably from 40 to 60% by weight, and even more preferably from 45 to 55% by weight. .

  The content of the phosphoric acid compound or salt thereof constituting component (c) preferably ranges from 0.1 to 5% by weight, more preferably from 0.2 to 3% by weight and even more preferably from 0.5 to 1.5% by weight.

  The percentage of the binder forming component (e) is preferably from 0.5 to 20% by weight, more preferably from 2 to 15% by weight and still more preferably from 3 to 10% by weight.

  (4) Fourth combination When the composition according to the present invention contains four components (a), (b), (c) and (f), the contents indicated below of the respective constituents is preferred in order to achieve the purpose of the present invention.

  The content of the fuels forming component (a) preferably ranges from 25 to 55% by weight, more preferably from 30 to 55% by weight and still more preferably from 35 to 45% by weight.

  The content of the oxidant forming component (b) preferably ranges from 35 to 70% by weight, more preferably from 40 to 60% by weight and even more preferably from 45 to 55% by weight.

  The content of the phosphoric acid compound or a single one of the latter forming component (c) preferably ranges from 0.1 to 5% by weight, more preferably from 0.2 to 3% by weight. and even more preferably from 0.5 to 1.5% by weight.

  The content of the additive forming component (f) preferably ranges from 0.1 to 15% by weight, more preferably from 0.5 to 10% by weight and even more preferably from 1 to 5% by weight. % by mass.

  (5) Fifth combination When the composition according to the present invention contains five components (a), (b), (c), (d) and (e), the contents indicated below of the respective constituents is preferred in view of achieve the purpose of the present invention.

  The fuel content forming component (a) preferably ranges from 25 to 55% by weight, more preferably from 30 to 55% by weight and even more preferably from 35 to 45% by weight.

  The content of the oxidant forming component (b) preferably ranges from 35 to 70% by weight, more preferably from 40 to 60% by weight and even more preferably from 45 to 55% by weight.

  The content of the phosphoric acid compound or salt thereof constituting component (c) preferably ranges from 0.1 to 5% by weight, more preferably from 0.2 to 3% by weight. % by weight and even more preferably from 0.5 to 1.5% by weight.

  The content of aluminum hydroxide and / or magnesium hydroxide forming component (d) preferably ranges from 0.5 to 15% by weight, more preferably from 2 to 12% by weight. and even more preferably from 3 to 10% by weight.

  The content of the binder forming component (e) preferably ranges from 0.5 to 20% by weight, more preferably from 2 to 15% by weight and still more preferably from 3 to 10% by weight. The percentage of content indicated above is preferable when component (e) is used in combination with component (d) since the flue gases can be purified without any loss of moldability.

  (6) Sixth combination When the composition according to the present invention contains five components (a), (b), (c), (d) and (f), the contents indicated below of the respective constituents is preferred in view of achieve the purpose of the present invention.

  The content of the fuel forming component (a) preferably ranges from 25 to 55% by weight, more preferably from 30 to 55% by weight and still more preferably from 35 to 45% by weight.

  The content of the oxidant forming component (b) preferably ranges from 35 to 70% by weight, more preferably from 40 to 60% by weight and even more preferably from 45 to 55% by weight.

  The content of the phosphoric acid compound or a salt thereof, constituting component (c), preferably ranges from 0.1 to 5% by weight, more preferably from 0.2 to 3% by weight. mass and even more preferably from 0.5 to 1.5% by weight.

  The content of the aluminum hydroxide and / or the magnesium hydroxide of component (d) preferably ranges from 0.5 to 15% by weight, more preferably from 2 to 12% by weight and from even more preferentially from 3 to 10% by weight.

  The content of the additive forming component (f) preferably ranges from 0.1 to 15% by weight, more preferably from 0.5 to 10% by weight and even more preferably from 1 to 5% by weight. % by mass.

  (7) Seventh combination When the composition according to the present invention contains five components (a), (b), (c), (d), (e) and (f), the contents indicated below of the respective constituents is preferable. in order to achieve an object of the present invention.

  The fuel content constituting component (a) preferably ranges from 25 to 55% by weight, more preferably from 30 to 55% by weight and still more preferably from 35 to 45% by weight.

  The content of the oxidant forming component (b) preferably ranges from 35 to 70% by weight, more preferably from 40 to 60% by weight and even more preferably from 45 to 55% by weight.

  The content of the phosphoric acid compound, or a salt thereof, forming component (c) preferably ranges from 0.1 to 5% by weight, more preferably from 0.2 to 3% by weight. mass and even more preferably from 0.5 to 1.5% by weight.

  The content of the aluminum hydroxide and / or the magnesium hydroxide forming component (d) preferably ranges from 0.5 to 15% by weight, more preferably from 2 to 12% by weight and even more preferably from 3 to 10% by weight.

  The binder content forming component (e) preferably ranges from 0.5 to 20% by weight, more preferably from 2 to 15% by weight and still more preferably from 3 to 10% by weight. . The percent content above is preferred when component (e) is used in combination with component (d), since the flue gases can be purified without any loss of moldability.

  The content of the additive forming component (f) preferably ranges from 0.1 to 15% by weight, more preferably from 0.5 to 10% by weight and even more preferably from 1 to 5% by weight. % by mass.

  Examples of compositions (1) Composition Example 1 (a) Guanidine nitrate 53.1% by weight (b) Basic copper nitrate 46.4% by weight (c) Tribasic aluminum phosphate 0.5% by weight ( 2) Composition Example 2 (a) Guanidine Nitrate 51.5% by Weight (b) Basic Copper Nitrate 45.0% by Weight (c) Sodium Tetrapolyphosphate 0.5% by Weight (d) Aluminum Hydroxide 3 0% by weight (3) Combination Example 3 (a) Guanidine nitrate 44.4% by weight (b) Basic copper nitrate 45.6% by weight (c) Tribasic aluminum phosphate 1.0% by weight (d) Aluminum hydroxide 5.0% by weight (e) CMCNa 4.0% by weight The gas generating composition according to the present invention can be molded into the desired shape and can in particular be prepared as a molded article. 30 having the shape of a cylinder with a single perforation, porous cylinder, or pellets. These molded articles may be made by a process in which water or an organic solvent is added and mixed with the gas-generating composition, and extrusion molding is carried out (in the case of the article). molded in the form of a single perforation cylinder or a porous cylinder), or by a method in which compression molding is performed using a pellet forming device. (In the case of a molded article in the form of pellets.

  The gas-generating compositions according to the present invention and the molded articles obtained with this composition can be used for example in air bag inflators (airbag) for the driver's side, an airbag inflator for a passenger side next to the driver, a side airbag inflator, an airbag inflator, a knee pad device, an inflatable seat belt inflation device , a tubular system inflator and a gas generator for a prestressing device in different types of vehicles.

  In addition, it is possible to use inflation devices using the gas generating composition according to the present invention and the molded article obtained with this composition in pyrotechnic type inflation devices, in which only a gas generating agent delivers a gas, or in a hybrid type, wherein gas delivery is provided by both a compressed gas such as argon, and a gas generating agent.

  Further, the gas generating composition according to the present invention and the molded article obtained therefrom may be used as an ignition agent referred to as an intensifier (or amplifier), etc. for transferring energy from a detonator or primer to the gas generating composition.

EXAMPLES

Example 1

  A mixture of 2081 g of guanidine nitrate, 2319 g of basic copper nitrate, 150 g of CMCNa, 400 g of aluminum hydroxide, 50 g of sodium polyphosphate and 735 g of sodium was mixed. The mixture was then extrusion-molded and subjected to cutting, drying, sieving, etc. processing steps. to obtain a molded article of a gas generating composition in the form of a single perforated perforated bead ("singleperforated") having an outer diameter of 4.3 mm, an inner diameter of 1.1 mm and a length of 4.1 mm.

  An amount of 39.9 g of the molded article of the gas generating composition was placed in a single driver side inflation device and tested using a 60 l gas cylinder ( a widely known test method described in N 98 of JP-A No. 2001-97176). As a result, the amount of vapor in the bottle was 692 mg for a maximum pressure in this tank of 181 kPa.

  In addition, this inflation device was actuated in a 2800 liter gas cylinder, and the concentrations of NOx, CO and NH3 in the exhaust gas were measured inside the gas cylinder. When tested with a 2800 1 gas cylinder, the inflation device under test was placed in an iron gas cylinder with a capacity of 2800 liters, and the concentrations of NO, NO2, CO and NH3 in the gas cylinder were measured after 3 minutes, 15 minutes and 30 minutes after the inflator was triggered; the average value of the gas concentration after 3 minutes, 15 minutes and 30 minutes was used as the concentration for each gas.

  The following results were obtained: NO2: 0 ppm, NO: 11 ppm, CO: 40 ppm, and NH3: 4 ppm. These results show that there was only a small amount of steam and that the exhaust was clean.

Claims (5)

  A gas generating composition comprising: (a) a fuel, (b) an oxidant, and (c) a compound selected from the group consisting of a phosphoric acid compound or a salt thereof.   2. gas generating composition according to claim 1, characterized in that the content of compound (c) in the composition ranges from 0.1 to 5 by mass.   3. gas generating composition according to claim 1 or 2, characterized in that it further comprises: (d) aluminum hydroxide and / or magnesium hydroxide.   4. gas generating composition according to any one of claims 1 to 3, characterized in that it further comprises: (e) a binder, and / or (f) an additive.   5. A gas generating composition molded article, in the form of an insulated perforation cylinder or a porous cylinder, as obtained by extrusion and molding of a generating composition generating a gas according to any one of Claims 1 to 4.